The attorney, Beth Brinkmann, a deputy assistant attorney general in the Civil Division, urged a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit to uphold a lower judge's ruling that dismissed a suit that tried to block enforcement of National Institutes of Health guidelines promulgated in 2009.

Federal law prohibits funding research "in which a human embryo or embryos are destroyed, discarded or knowingly subjected to risk of injury or death." Brinkmann told the appeals court panel that the restrictions do not apply to projects in which a stem cell line was originally created.

The D.C. Circuit panel today was Chief Judge David Sentelle and judges Karen LeCraft Henderson and Janice Rogers Brown. Henderson was on the panel last year that overturned U.S. District Judge Royce Lamberth, who had granted a request for a preliminary injunction. (The other two judges were Douglas Ginsburg and Thomas Griffith. Henderson voted in support of the preliminary injunction.)

Sentelle today questioned whether and to what extent the earlier D.C. Circuit ruling was binding on the appeals court. Brinkmann said the law of the case and the law of the circuit should favor the government. The appeals court, she said, was being asked to decide the same legal claim the court already rejected.

Watson argued on behalf of two plaintiffs, doctors James Sherley and Theresa Deisher, who perform research on adult stem cells.

Watson, who practices in appellate litigation, said among other things that the NIH failed to take notice of more than 30,000 comments addressing scientific and ethical concerns about the guidelines.

Sentelle suggested in questioning that comments may have been outside the scope of the executive order President Barack Obama issued.

Justice Department lawyers said in court papers that Obama's executive order directed NIH to assess new guidelines over human embryonic stem cell research. The order did not mandate that the NIH fund any such research.

The appeals court did not immediately rule this morning.

This post was updated to reflect the identity of the D.C. Circuit panel that heard an earlier dispute in the case.